Absorption refrigeration system having plural temperature cooling structure



KOGEL ABSORPTION REFRIGERATION SYSTEM HAVING March 29, 1955 w,

PLURAL TEMPERATURE 000mm; STRUCTURE Filed Jan. 17, 1951 2 Sheets-Sheet 1 March 29, 1955 w, KOGEL ABSORPTION REFRIGERATION SYSTEM HAVING PLURAL TEMPERATURE COOLING STRUCTURE 2 Sheets-Sheet 2 Filed Jan. 17, 1951 VIIII'IIII'IIIIIIII'4 f United States Patent ABSORPTION REFRIGERATION SYSTEM HAVING PLURAL TEMPERATURE CGOLING STRUCTURE Wilhelm Georg Kogel, Stockholm, Sweden, assignor to Aktiebolagct Eieirtrolux, Stockholm, Sweden, a corporation of Sweden Application Ilanuary 17, 1951, Serial No. 206,372 Claims priority, application Sweden January 23, 1950 11 Claims. (Cl. 62-99) My invention relates to refrigeration, and more particularly concerns cooling of a storage compartment of a refrigerator. More particularly, the invention relates to such cooling of a refrigerator with the aid of a plural temperature cooling structure of a refrigeration system employing an inert gas or auxiliary agent.

it is an object of my invention to provide an improvement for cooling a storage compartment of a refrigerator by obtaining better distribution of cooling effect produced by several cooling elements operable at different temperatures.

I accomplish this by producing a refrigerating effect beiow the freezing temperature of water at a first region of a space and a refrigerating effect above the freezing temperature of water at a second region of the space, circulating air in the space, flowing such circulating air in the second region without restriction, and varying the quantity of circulating air permitted to flow in the first region. perature region is located below the first or low ternperature region, and the quantity of circulating air which passeg through the second region to the first region is vane The cooling effects are produced by low and higher temperature cooling elements from which cooling effects are transmitted to air to induce natural circulation thereof in the space. Upstream components of air circulating in the space reach and come in intimate contact with the low temperature cooling element. Further, the higher temperature cooling element, which is formed to provide a reiatively extensive heat transfer surface and is permeable to air, provides a restriction to flow of air therethrough and enables upstream components of circulating air to pass therethrough and come in thermal transfer with the low temperature cooling element at a rate which is dependent upon the temperature of such low temperature cooling element.

The invention, together with the above and other objects and advantages thereof, will become apparent as the following description proceeds, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of my invention, reference may be had to the following description taken in connection with the accompanying drawings in which:

Fig. 1 illustrates more or less diagrammatically an absorption refrigeration system of the inert gas type to which the invention is applied;

Fig. 2 is a fragmentary sectional view, looking toward the rear of a storage space of a refrigerator, more or less diagrammatically illustrating a preferred form of evaporator structure embodying the invention and forming a part of a refrigeration system of the inert gas type exemplified by the system shown in Fig. 1;

Fig. 3 is a horizontal sectional View taken at line 3-3 of Fig. 2;

Fig. 4 is a side elevation of the evaporator structure shown in Figs. 2 and 3, partly broken away and in section, to illustrate details more clearly; and

Fig. 5 is a fragmentary sectional view illustrating a modification of the bottom part of the evaporator structure of Figs. 2 to 4 inclusive.

Referring to Fig. 2, a household refrigerator 1.0 having a storage space 11 is subdivided into a plurality of compartments 12 and 13 one above the. other andv arp More particularly, the second or higher tem-' ranged to be cooled by a plurality of evaporators 14 and 15 operable at different temperatures. The subdivided compartments 12 and 13 extend between the lateral side walls 16 of the storage space, and the upper compartment 12 is adapted to be maintained at a low temperature for freezing water and other matter as well as for storing frozen food packages.

In absorption refrigeration systems of the inert gas type having evaporators 14 and 15 adapted to operate at different temperatures, such evaporators are generally formed of piping which are shaped as coils and connected by conduits to other parts of the system for circulation of inert gas as well as to supply liquid refrigerant to the evaporators. When such an absorption refrigeration system is employed in the cabinet of a household refrigerator, the evaporators 14 and 15 and connections thereto are usually inserted into the storage space 11 at the rear of the cabinet in any suitable manner, such as, for example, through an opening in the Irjear adapted to be closed by an insulated closure mem- An absorption refrigeration system of the inert gas type to which the invention is applied is more or less diagrammatically shown in Fig. 1. In order to simplify Fig. l, the evaporators 14 and 15 have been illustrated apart from a household refrigerator having subdivided compartments one above the other. The absorption refrigeration system shown in Fig. l is of a uniform pressure type in which an inert gas or auxiliary pressure equalizing fluid is employed. In a system of this type a refrigerant fluid, such as liquid ammonia, for example, is introduced through a conduit 17 into the evaporators 14 and 15. I

The refrigerant fluid in evaporators l4 and 15 evaporates and diffuses into an inert gas, such as hydrogen, for example, to produce a refrigerating effect and abstract heat from the surroundings. The resulting gas mixture of refrigerant and inert gas flows from evaporators 14 and 15 through an inner passage 18 of a gas heat exchanger 19 and vertical conduit 20 into an absorber comprising a vessel 21 and a looped coil 22. In the absorber vessel 21 and coil 22 refrigerant vapor is absorbed by a suitable absorbent, such as water, for example, which is introduced into coil 22 through a conduit 23. The hydrogen or inert gas, which is practically insoluble and weak in refrigerant, is returned to the evaporators 14 and 15 through an outer passage 24 of the gas heat exchanger 19 and a conduit 25.

The circulation of gas in the gas circuit just described is due to the difference in specific weight of the columns of gas rich and weak, respectively, in refrigerant vapor. Since the column of gas rich in refrigerant vapor and flowing from evaporators 14 and 15 to the absorber coil 22 is heavier than the gas weak in refrigerant and flowing from such coil to the evaporators I4 and 15, a force is produced or developed within the 'systemfor causing circulation of inert gas in the manner described.

From the vessel 21 enriched absorption liquid flows through a conduit 26 and an inner passage 27 of a liquid heat exchanger 28 into the lower end of a vapor lift pump 29 of a generator unit 30. The generator unit 3% comprises a heating tube 31 having the vapor lift pump 29 and a boiler pipe 32 in thermal exchange relation therewith, as by welding, for example. By heating generator unit 3%, as by anelectrical heating element within the lower part of heating tube 31 or by a fluid fuel burner 33, for example, liquid from the inner'passage 27 of the liquid heat exchanger is raised by vapor lift' action through pump 29 into the upper part of the boiler pipe 32. The liberated refrigerant vapor entering boiler pipe 32 through the pump 29, and also vapor expelled from solution in the boiler pipe, flows upward-1y into an air cooled condenser 34 provided with a plurality of cooling fins 35.

Refrigerant vapor is liquefied. in the condenser 34 and returned to the evaporators 14v and 15 through the con duit .17 to complete the refrigerating cycle. Gravity flow of liquid refrigerantis effected through the evaporators, the lower evaporator 15 receiving liquid refrig erant through a conduit 36 from the upper evaporator 14. The lower end of condenser 34 is connected by a conduit 37 to the gas.ci-rcuit', a-s to the upper part of the absorber coil 22, for example, so that any non-condensable gas that may pass into the condenser will fiow to the gas circuit and not be trapped in the condenser. The weakened absorption liquid, from which refrigerant vapor has been expelled, is conducted from boiler pipe 32 through a conduit 38, the outer passage 39 of the liquid heat exchanger 28 and conduit 23 into the upper part of absorber coil 22.

It will be understood that the evaporators 14 and in Fig. 1 are diagrammatically shown in the form of a continuous coil, and that in Figs. 2 to 4 a practical form of the evaporator structure in accord with the invention is illustrated in which the evaporators 14 and 15 comprise horizontally disposed coils at different levels. The evaporator coils 14 and 15 are connected in series relation, and, while all of the conduit connections associated with the coils are not illustrated in Fig. 2, it is to be understood that such connections are generally like those diagrammatically shown in Fig. 1. Accordingly, flow of fluids takes place in the evaporator coils 14 and 15 of Fig. 2 in the manner shown in Fig. 1 whereby inert gas from conduit enters the upper evaporator coil 14 at the right-hand end thereof at and flows therethrough in the presence of and in counterflow to liquid refrigerant which passes from conduit 17 into the left-hand end 41 of the upper coil 14. The lower evaporator coil 15 receives inert gas from the upper coil 14 through a vertical connection like that indicated at 42 in Fig. 1 and also receives unevaporated liquid refrigerant from the coil 14 through a connection like the conduit 36. In Fig. 2 liquid refrigerant and inert gas enter the right-hand end 43 of the lower coil 15 and flow therethrough in the presence of each other. In order to obtain good distribution of liquid refrigerant in the evaporator coils 14 and 15 and promote evaporation and dilfusion of refrigerant fluid into the inert gas, the coils may be provided with suitable inserts, such as wire coils, for example.

The evaporator coils 14 and 15 are associated with a box-like container 44 which extends substantially over the entire width and depth of the storage space 11 and serves as the partition providing the compartments 12 and 13. The upper evaporator coil 14 is in thermal exchange relation with the underside of the top horizontal wall 45 of the container 44, and the lower evaporator coil 15 is in thermal exchange relation with the top surface of the bottom horizontal wall 46 of the container. It will be seen that the top horizontal wall or plate 45 of the partition or container 44 is provided with an upstanding rim 47 at the peripheral edge thereof and that one portion of the top plate is at a slightly lower level than the other portion thereof. However, each horizontally disposed evaporator coil 14 and 15 is located essentially in a single horizontal plane and the coils are vertically spaced apart within the partition.

In order to drain water and other liquid which may collect on the top horizontal plate 45, suitable drain openings 48 may be provided at different regions thereof. As best seen in Fig. 4, an outwardly extending flange 49 is formed at the rear of the partition or container 44 to facilitate fastening the latter in position within the cabinet 10. If desired, the flange 49 may be fixed to the closure member provided to close the opening at the rear of the cabinet and through which the evaporator coils 14 and 15 are inserted into the space 11. In any event, it is to be understood that the flange 49 can form a part of the inner lining of the storage space 11 and fixed in place in any suitable manner.

Since the inert gas flows successively through the evaporator coils 14 and 15, the gas in the upper evaporator coil 14 contains a lesser amount of refrigerant vapor than the gas in the lower evaporator coil 15. The partial vapor pressure of the refrigerant is a gradient, so that the temperature of liquid refrigerant in the evaporator coils is also a gradient, the evaporating temperature of liquid being lower in the upper evaporating coil 14 which constitutes the freezing portion of the evaporator structure.

The refrigerating effect produced by the upper evaporator coil 14, which is adapted to be operated at temperatures below freezing, is primarily utilized to effect cooling of the upper compartment 12 which is defined by the partition 44 and the thermally insulated walls of the refrigerator 10. Accordingly, the upper compartment 12 serves as a freezing space which is adapted to receive ice trays, frozen food packages and other matter to be frozen. The refrigerating effect produced by the lower evaporator coil 15, which is adapted to be operated at a higher temperature than that of evaporator coil 14 and desirably above freezing, is primarily utilized to cool air in the lower compartment 13. The bottom horizontal wall or plate 46 of the container 44 in and of itself forms a relatively extensive heat transfer surface to promote cooling of air flowing in intimate contact therewith. To increase the effective heat transfer surface to promote such cooling of air in the lower compartment 13, a plurality of heat transfer members 50 desirably are fixed, as by welding, for example, to the underside of the bottom plate 46. The heat transfer members 50, which are U-shaped in section and the spaced apart sides or arms of which extend vertically downward, are arranged more or less parallel to the lateral side walls 51 of the partition or container 46. Essentially, the partition or container 44 constitutes a cooling structure in which the lower evaporator coil 15 and bottom portion of the container and heat transfer members 50 associated therewith constitute a high temperature cooling element having a relatively extensive heat transfer. Similarly, the top horizontal plate 45 of the container 44 and upper evaporator coil 14 in heat exchange relation therewith constitute a low temperature cooling element.

The partition 44 in Fig. 2 is slightly narrower than the distance between the lateral side walls 16 of the cabinet, thus providing gaps 52 between the partition and cabinet side walls. Since the evaporator coils 14 and 15 are connected by conduits to other parts of the refrigeration system and the container or partition 44 is fixed to such coils, the partition essentially can be maintained in position in space 11 without further supporting provisions. In order to prevent circulation of air between the upper and lower compartments 12 and 13, suitable closure members 53 are provided to close the gaps 52 at regions approximately at the level of the top horizonal plate 45. Hence, the partition 44 extends substantially over the entire width and depth of the storage space 11, and the upper freezing section may be provided with a separate hinged closure member (not shown) to keep such upper section closed when access only to the lower compartment 13 is desired.

It has been proposed heretofore to provide a partition like that just described in which the cooling effect produced by one of the evaporator coils is predominantly made available to effect cooling of one of the compartments at one side of the partition, and the cooling effect produced by the other of the evaporator coils is predominantly made available to effect cooling of the other compartment at the opposite side of the partition. In order to insure an adequately low temperature being maintained in the lower compartment 13 under all operating conditions encountered, especially when the higher temperature evaporator coil 15 is operating substantially at or near the freezing temperature of water, it has been necessary to provide heat transfer members at the bottom horizontal plate 46 which are relatively large in size and occupy a substantial part of the space in the lower compartment 13 that otherwise could be gainfully employed for food preservation purposes.

In accordance with my invention the partition 44 is formed with slots or openings 54 and 55 in the bottom horizontal plate 46 and side walls 51 thereof, respectively, to enable air circulating in the lower compartment 13 to be cooled by thermal transfer with the low temperature C00lll1g element of which evaporator coil 14 forms a part only after being initially cooled by thermal transfer with the higher temperature cooling element which includes evaporator coil 15.

When the refrigeration system described above is being operated, air in the compartment 13, upon being cooled by thermal transfer with the evaporator structure formed by the partition 44 and evaporator coils therein, flows downward in the lower compartment to replace warmer alr whrch flows upward and passes through the slots 55 in the lateral side walls 51 of the partition and the slots 54 in the bottom plate 46 which are located adjacent the side Walls 51. This natural circulation of air in the lower compartment 13, which is indicated by the arrows in Fig. 2, is due to the difference in specific weights of air at different temperatures.

The warmer air flowing upward in the lower compartment 13 alongside the lateral side walls 16 first comes ext-04,926

into intimate contact with the relatively extensive heat transfer surface forming a part of the higher temperature cooling element with which lower evaporator coil 15 is asociated. Hence, initial cooling of upwardly flowing air in the lower compartment 13 is effected when such air contacts and sweeps over the bottom horizontal plate 46 and heat transfer members 50 at the vicinity of the slots 54 adjacent the lateral side walls 51 of the partition, and also flows in intimate contact with the lower portions of the side walls 51 below the slots 53.

After passing through the. slots or openings 54 and 55 into the interior of the partition 44, such partially cooled air then flows in intimate contact with the low temperature cooling element of which the upper evaporator coil 14 forms a part. Hence, further cooling of air takes place when it contacts and sweeps over the underside of the top horizontal plate 45 and the evaporator coil 14 in thermal contact therewith. Such cooled air then flows downward through the slots or openings 54 located between the extreme end openings in the bottom horizontal plate 45.

By making use of the low temperature cooling element to effect cooling of air circulating in the lower compartment 13, the latter compartment can be maintained at an adequately low temperature without the necessity of employing unduly large heat transfer members at the underside of the bottom horizontal plate 45 of the partition 44. Accordingly, the cooling structure formed by the partition 44 is of minimum overall size and the heat transfer members 50 are of such size that an optimum amount of space is obtained in the interior of the cabinet for useful food preservation purposes.

It will be understood that the gaps 52 between the partition 44 and lateral side walls 16 of the cabinet are sufficiently wide to promote natural circulation of air in lower compartment 13 in the manner just described. By way of example and without limitation, the width of the t gaps 52 may be approximately the same as the width of the slots or elongated openings 54 and 55, respectively. Cooling structures like that shown and described have been successively used in practice and have demonstrated that adequately low temperatures can be maintained in the lower compartment 13 without adversely influencing to any appreciable extent the temperature at which the freezing compartment 12 is maintained by the low temperature evaporator coil 14. This indicates that suflicient initial cooling of upwardly flowing air is effected by the high temperature cooling element of which the evaporator coil 15 forms a part, so that cooling effect is transmitted from the low temperature cooling element to the partially cooled air in a manner which does not materially affect the primary function of transmitting cooling effect to the freezing section 12 by the low temperature evaporator coil 14. Therefore, some of the cooling effect produced by the low temperature evaporator coil 14 can be safely diverted from its primary function of cooling freezing section 12 to promote cooling of air in the lower compartment 13 without seriously disturbing the ice freezing capacity of the upper compartment or freezing section section 12.

For example, when the lower evaporator coil 15 is being operated at a temperature at or near the freezing temperature of water, such cooling effect promotes initial cooling of upwardly flowing air in the lower compartment 13. During those periods when the load in the freezing section 12 is relatively light and the low temperature evaporator coil 14 is functioning primarily to maintain a desired low temperature in the freezing section, the low temperature cooling element may be at a temperature of -5 to l0 C. 'or' even lower. Under such operating conditions the temperature differential between the initially cooled air in partition 44 and low temperature cooling element is relatively high, and the transfer of cooling effect by the low temperature cooling element to such air will be substantial and at the same time impart sharp downward flow movement to the air to promote natural circulation, such transfer of cooling effect being accomplished without any appreciable rise in temperature of the relatively unloaded low temperature cooling element.

During those periods when the load on the freezing section 12 is increased, as when ice trays containing water to be frozen are positioned in the freezing section, for example, the temperature of the low temperature cooling element increases toward the freezing temperature of water. Under these conditions the temperature diflferential between'initially' cooled air in partition 44 and the low temperature cooling element is, reduced, and a greater portion of the cooling effect produced by the low temperature evaporator coil 14 is made available to freeze the water in the ice trays. For example, if the load on the freezing section were increased to such an extent that the temperature of the low temperature cooling element momentarily approached the freezing temperature of water, there would be no substantial difference in temperature between the low temperature cooling element and air in the partition that has been initially cooled in the manner previously explained. In such case practically all of the cooling effect produced by the low temperature evaporator coil 14 would be effectively employed to effect cooling of the freezing section 12 which is its primary function. When the load on the freezing section 12 is reduced, then some of the cooling effect produced by the low temperature evaporator coil 15 can again be usefully diverted to promote cooling of air circulating in the lower compartment 13.

The heat transfer surfaces or horizontal top and bottom plates 45 and 46 of the low and higher temperature cooling elements, respectively, define a horizontally extending path of flow therebetween in which flow of air is restricted relative to flow of air in the compartment 13 below the higher temperature cooling element of which coil 15 forms a part. When there is no substantial difference in temperature between the low temperature cooling element and air in the partition that has been initially cooled by the higher temperature cooling element, the low temperature cooling element no longer imparts a sharp downward flow movement to air in the partition 44 Under these conditions less air in the partition 44 moves downwardly therefrom into the lower compartment 13 and less air in the partition is displaced by air from the lower compartment 13 that has been initially cooled by the higher temperature cooling element. Hence, circulation of air in the horizontally extending path of flow formed within the partition 44 in intimate contact with the heat transfer surface of the low temperature cooling element increases and decreases, respectively, with decrease and increase in temperature of the low temperature cooling element.

The heat transfer members 5% serve to increase the effective heat transfer surface of the higher temperature and also may be referred to as surface enlarging members. instead of providing separate heat transfer members 50 which must be fixed to the bottom horizontal plate 46 of the partition 44, such heat transfer or surface enlarging members may be provided in a manner generally like that shown in Fig. 5 which is a fragmentary view of a partition 44:: illustrating a modification of the invention. In Fig. 5 the lower evaporator coil 15a is fixed,

. as by welding, to the bottom horizontal plate 46a of the partition 44a. The plate 46a is provided with fins 50a and Silb which are formed by the material stamped to produce the elongated slots 54a.

The fins Sfla and 50b are deflected downwardly in different ways to promote circulation of air in the lower compartment 13 in the manner indicated in Fig. 2 and described above. it will be seen that the fins 59a near and adjacent the lateral sides of the partition slope downwardly at an acute angle from the horizontal and in a direction from the center of the partition toward the lateral sides thereof. The fins Stib at and near the central region of the partition extend straight downward and form a right angle with the horizontal bottom plate 46a. The fins Sfla are positioned and shaped to promote upward flow of air into the interior of the partition at regions adjacent the lateral side walls 16 of the space 11. Hence, the fins 50a serve as deflectors to deflect upward flowing air into the interior of the partition and direct such air toward the top horizontal plate of the partition. Also, the fins 50a serve as heat transfer members to promote effective initially cooling of air passing over the surfaces thereof. The openings at which the fins 50!) are located provide an unobstructed downward path of movement for air which has been cooled.

In view of the foregoing it will now be understood that cooling effect is transmitted to the upper freezing compartment 12 from the low temperature cooling element which includes the upper evaporator coil 14. The cooling structure providing the higher temperature cooling element, which includestheevaporator coil '15 and bottom plate 46 and heat transfer members associated therewith, provides a relatively extensive heat transfer surface which is distributed over a relatively wide area essentially in a horizontal plane at the ceiling of the lower compartment 13. The higher temperature cooling structure is apertured at 54 and 55, as previously explained, to enable upstream components of air circulating in compartment 13 to reach and come in intimate contact with the low temperature cooling element only after being initially cooled by the higher temperature cooling element.

In Fig. 2 it will be seen that cooling effect is initially transmitted by the higher temperature cooling element to upstream components of circulating air at regions adjacent the bounding side walls 16 of the lower compartment 13. The cooled air flows downwardly in compartment 13 at regions removed from the lateral side walls 16. In the partition 44 the upstream components of air, after being initially cooled by the higher temperature cooling element, flow in thermal transfer relation with the low temperature cooling element while passing horizontally to a zone in vertical alignment with the regions at which cooled air moves downwardly in compartment 13.

As previously explained, only a negligible quantity of air flows in thermal transfer with the low temperature cooling element when the temperature of the latter rises to a value normally reached when it is functioning to freeze water, as when several ice trays containing water to be frozen, are positioned on plate 45 in thermal relation with the low temperature cooling element. Under such conditions the apertured structure constituting the higher temperature cooling element serves to restrict flow of air therethrough and enables upstream components of air to pass in thermal transfer relation with the low temperature cooling element at a rate which is dependent upon the temperature of the latter. Stated another way, an arrangement is provided in which the structure constituting the higher temperature cooling element acts to vary the quantity of air passing therehrough and flowing in thermal transfer with the low temperature cooling element, such functioning of the higher temperature cooling element being effected responsive to the temperature of the low temperature cooling element.

Accordingly, the structure providing the higher temperature cooling element is capable of developing resistance to flow of air therethrough which is of a magnitude relatively great compared to the driving force imparted to air as the result of cooling thereof to induce natural circulation of air in the lower compartment 13. Asexplained above, the relation of the magnitude of the resistance to air flow through the higher temperature cooling element to the driving force imparted to the air is such that the quantity of air flowing in thermal relation with the low temperature cooling element decreases with rise in temperature thereof. Hence, an arrangement has been provided in which the higher temperature cooling element acts to control the proportion of air flowing in contact with the low temperature cooling element and thereby vary the extent of cooling effected by the latter. Under certain operating conditions, therefore, the higher temperature cooling element functions to by-pass air around the higher located low temperature cooling element and to all practical purposes cause air to flow in thermal relation only with the higher temperature cooling element.

Modifications of the embodiments of my invention which I have described will occur to those skilled in the art, so that I desire my invention not to be limited to the particular arrangements set forth. Therefore, I intend in the claims to cover all those modifications which do not depart from the spirit and scope of my invention.

What is claimed is:

1. In a refrigerator including a cabinet having a thermally insulated interior and an absorption refrigeration system associated therewith having a circuit for inert gas which includes low and higher temperature evaporator coils in which refrigerant fluid evaporates in the presence of the gas, a horizontally extending member for the cabinet interior comprising structure providing a housing having spaced apart top and bottom horizontally disposed plates, said low temperature evaporator coil being in thermal relation with said top plate and said higher temperature evaporator (3011 being in thermal relation with said. bottom plate, and means including said bottom plate providing a relatively extensive heat transfer surface to promote cooling of air circulating in the cabinet beneath said horizontally extending member, said housing having openings to enable upstream components of such circulating air to pass into said housing in thermal transfer relation with said top p ate.

2. Refrigerator apparatus as set forth in claim 1 in which the width of said housing is less than the width of the thermally insulated interior of the cabinet and the side walls of the housing are formed with openings to enable upstream components of air circulating beneath said horizontally extending member to pass therethrough, the space between the side walls of the cabinet interior and side walls of the housing providing gaps into which upstream air components are directed.

3. Refrigerator apparatus like that set forth in claim 1 in which said higher temperature evaporator coil includes spaced apart straight sections and connecting bends, such straight sections being disposed substantially parallel to the lateral side walls of the cabinet interior, and the openings in said housing being formed in said bottom plate in the portions thereof between the straight sections of said coil.

4. Refrigerator apparatus as set forth in claim 1 in which material that forms a part of said bottom plate and is stamped to provide the openings in said housing, such stamped material serving as heat transfer members which are integral with said bottom plate.

5. Refrigerator apparatus as set forth in claim 1 in which said housing is formed with openings in the bottom plate thereof.

6. In a refrigerator including a cabinet having a thermally insulated interior and an absorption refrigeration system associated therewith having a circuit for inert gas which includes low and higher temperature coils in which refrigerant fluid evaporates in the presence of the gas, a horizontally extending partition for the cabinet interior having a horizontally disposed plate forming the top wall thereof and means including a plurality of vertically disposed heat dissipating elements fornnng the bottom wall thereof, said walls having a space or gap therebetween, said low temperature coil being in thermal relation with said plate and said higher temperature evaporator coil being in thermal relation with the heat dissipating elements of the bottom wall, the heat dissipating elements of the bottom wall providmg a relatively extensive heat transfer surface to promote cooling of air circulating in the cabinet beneath said hor1zontally extending partition, said means forming the bottom wall having openings to enable upstream components of such circulating air to pass into the space or gap between the top and bottom walls of the partition in thermal transfer relation with the top plate.

7. A cabinet having an insulated interior, a low temoperature cooling element at a first level and a hi her temperature cooling element which is beneath said low temperature cooling element and at a scond lower level, partition means including said low and higher temperature cooling elements for dividing the interior of the cabinet to provide a first compartment extending upward from said low temperature cooling element and a second compartment extending downward from said higher temperature cooling element, each of said cooling elements having a heat transfer surface for cooling air flowing in intimate contact therewith, the heat transfer surfaces of said low and higher temperature cooling elements defining the top and bottom walls of a horizontally disposed gap in said partition means which forms a path of flow for air in which flow of air is restricted relative to flow of air in the second compartment below said higher temperature cooling element, the air in the interior of the cabinet in the second compartment circulating therein by natural draft circulation and passing freely in intimate contact with the heat transfer surface of said higher temperature cooling element and also passing into the gap in said partition means in intimate contact with the heat transfer surface of said low temperature cooling element at a rate which is dependent upon the temperature of said low temperature cooling element, such circulation of air in the gap in said partition means in intimate contact with the heat transfer surface of said low temperature cooling element increasing and decreasing with decrease and increase, respectively, in temperature of said low temperature cooling element.

8. In a refrigerator, a cabinet having an insulated interior, an absorption refrigeration system having a circuit for inert gas which includes low and higher temperature cooling elements in which refrigerant fluid evaporates in the presence of the gas, said low temperature cooling element being disposed above and overlying said higher temperature cooling element, said low temperature cooling element having a heat transfer surface for cooling air flowing in intimate contact therewith which is distributed over a definite cross-sectional area in the cabinet interior, means providing a relatively extensive heat transfer surface for said higher temperature cooling element which is essentially co-extensive with the heat transfer surface of said low temperature cooling element, partition means including said low and higher temperature cooling elements for dividing the interior of the cabinet to provide a first compartment extending upward from said low temperature cooling element and a second compartment extending downward from said higher temperature cooling element, the heat transfer surfaces of said low and higher temperature cooling elements defining a horizontally disposed gap in said partition means which forms a path of flow for air, the heat transfer surface of said higher temperature cooling element being apertured to offer such resistance to flow of air therethrough that upstream components of a major portion of the air circulating in the second compartment will be initially cooled by said higher temperature cooling element and thereafter pass into the gap in said partition means and flow in thermal relation with the heat transfer surface of said low temperature cooling element at a rate dependent upon the temperature of said last-mentioned cooling element.

9. In a refrigerator, a cabinet having an insulated interior, an absorption refrigeration system having a circuit for inert gas which includes low and higher temperature cooling elements in which refrigerant fluid evaporates in the presence of the gas, said low temperature cooling element being disposed above and overlying said higher temperature cooling element, said low temperature-cooling element having a heat transfer surface, means providing an apertured heat transfer surface for said higher temperature cooling element, partition means including said low and higher temperature cooling elements for dividing the interior of the cabinet to provide a first compartment extending upward from said low temperature cooling element and a second compartment extending downward from said higher temperature cooling element, the heat transfer surfaces of said low and higher temperature cooling elements defining a horizontally disposed gap therebetween forming a path of flow for air, and means including said apertured heat transfer surface for flowing air circulating in the second compartment into the gap in thermal transfer relation with the heat transfer means of said low temperature cooling element only after passing through said apertured heat transfer surface and after being subjected to cooling effect by said higher temperature cooling element, such flow of air into said gap through said apertured heat transfer surface being effected at a rate responsive to the temperature of said low temperature cooling element.

10. In a refrigerator having a thermally insulated interior, refrigeration apparatus including low and higher temperature cooling elements in the cabinet interior, each of said cooling elements having a heat transfer surface, partition means including said low and higher temperature cooling elements for dividing the cabinet interior to provide a first compartment extending upward from one of said cooling elements and a second compartment extending downward from the other of said cooling elements, the heat transfer surfaces of said low and higher temperature cooling elements defining a horizontally disposed gap therebetween forming a path of flow for air, and means influenced by the temperature of said low temperature cooling element for regulating the rate at which air, that circulates in one of said compartments defined in part by said higher temperature cooling clement, flows into said gap in intimate contact with the heat transfer surface of said low temperature cooling element only after such air has been initially subjected to cooling effect by the heat transfer surface of said higher temperature cooling element, said last-mentioned means including the heat transfer surface of said higher temperature cooling element having a plurality of paths of flow for air therethrough between said one compartment and said gap.

11. In a refrigerator having a thermally insulated interior, refrigeration apparatus including low and higher temperature cooling elements in the cabinet interior, said low temperature cooling element being above said higher temperature cooling element, each of said cooling elements having a heat transfer surface, partition means including said low and higher temperature cooling elements for dividing the cabinet interior to provide a first compartment extending vertically upward from said low temperature cooling element and a second compartment extending downward from said higher temperature cooling element, the heat transfer surfaces of said low and higher temperature cooling elements defining a horizontally disposed gap therebetween forming a path of flow for air, and means influenced by the temperature of said low temperature cooling element for regulating the rate at which air circulating in the second compartment flows into said gap in intimate contact with the heat transfer surface of said low temperature cooling element only after such air has been initially subjected to cooling effect by the heat transfer surface of said higher temperature cooling element, said last-mentioned means including the heat transfer surface of said higher temperature cooling element having a plurality of paths of flow for air therethrough between the second compartment and said gap.

References Cited in the file of this patent UNITED STATES PATENTS 2,328,189 Brace Aug. 31, 1943 2,345,453 Brace Mar. 28, 1944 2,363,385 Bixler Nov. 21, 1944 2,504,784 Ashby Apr. 18, 1950 2,520,530 Coons Aug. 29, 1950 FOREIGN PATENTS 269,609 Switzerland Oct. 16, 1950 920,544 France Apr. 10, 1947 

